Null Pointer

[nickyeng]

Hi

i have the following code. compiled no error. but in runtime it give me error message :

Error Message:

java.lang.NullPointerException
	at com.sun.midp.ssl.MD5.doFinal(+4)
	at AESEncrypter.genHash(+55)
	at MEMerchantInterface$HelpSelector.commandAction(+734)
	at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+282)
	at javax.microedition.lcdui.Display$DisplayManagerImpl.commandAction(+10)
	at com.sun.midp.lcdui.DefaultEventHandler.commandEvent(+68)
	at com.sun.midp.lcdui.AutomatedEventHandler.commandEvent(+47)
	at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.run(+250)

Code:

public static String genHash(String s)
		 throws java.security.NoSuchAlgorithmException {
			 
		
		 byte[] ab = null;
		
		 try {
			 com.sun.midp.ssl.MessageDigest md = com.sun.midp.ssl.MessageDigest.getInstance(com.sun.midp.ssl.MessageDigest.ALG_MD5, true);
			
			 md.update(s.getBytes(), 0, s.length()) ;

			 System.out.println("test1");
			 
			 System.out.println("tested ab");
			 
			 short sh = md.doFinal(s.getBytes(), 0, s.length(), ab, 0 );
			 
			 System.out.println("called");
			 
		 } catch (CryptoException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		 }
 
		 return toHexString(ab) ;
	}

I used System.out.prin tln to debug, "tested ab" printed but "called" IS NOT printed, so i guess the null pointer is came from short sh = ..........

Why nullpointer?
I dont see which one is null pointer.

anyone help ?
thanks.

[amitpatel66]

Hi

i have the following code. compiled no error. but in runtime it give me error message :

Error Message:

java.lang.NullPointerException
	at com.sun.midp.ssl.MD5.doFinal(+4)
	at AESEncrypter.genHash(+55)
	at MEMerchantInterface$HelpSelector.commandAction(+734)
	at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+282)
	at javax.microedition.lcdui.Display$DisplayManagerImpl.commandAction(+10)
	at com.sun.midp.lcdui.DefaultEventHandler.commandEvent(+68)
	at com.sun.midp.lcdui.AutomatedEventHandler.commandEvent(+47)
	at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.run(+250)

Code:

public static String genHash(String s)
		 throws java.security.NoSuchAlgorithmException {
			 
		
		 byte[] ab = null;
		
		 try {
			 com.sun.midp.ssl.MessageDigest md = com.sun.midp.ssl.MessageDigest.getInstance(com.sun.midp.ssl.MessageDigest.ALG_MD5, true);
			
			 md.update(s.getBytes(), 0, s.length()) ;

			 System.out.println("test1");
			 
			 System.out.println("tested ab");
			 
			 short sh = md.doFinal(s.getBytes(), 0, s.length(), ab, 0 );
			 
			 System.out.println("called");
			 
		 } catch (CryptoException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		 }
 
		 return toHexString(ab) ;
	}

I used System.out.prin tln to debug, "tested ab" printed but "called" IS NOT printed, so i guess the null pointer is came from short sh = ..........

Why nullpointer?
I dont see which one is null pointer.

anyone help ?
thanks.

What is the string that you are passing to genHash function??

[samido]

What is it you trying to de dude? hashing the string? ....

[r035198x]

Hi

i have the following code. compiled no error. but in runtime it give me error message :

Error Message:

java.lang.NullPointerException
	at com.sun.midp.ssl.MD5.doFinal(+4)
	at AESEncrypter.genHash(+55)
	at MEMerchantInterface$HelpSelector.commandAction(+734)
	at javax.microedition.lcdui.Display$DisplayAccessor.commandAction(+282)
	at javax.microedition.lcdui.Display$DisplayManagerImpl.commandAction(+10)
	at com.sun.midp.lcdui.DefaultEventHandler.commandEvent(+68)
	at com.sun.midp.lcdui.AutomatedEventHandler.commandEvent(+47)
	at com.sun.midp.lcdui.DefaultEventHandler$QueuedEventHandler.run(+250)

Code:

public static String genHash(String s)
		 throws java.security.NoSuchAlgorithmException {
			 
		
		 byte[] ab = null;
		
		 try {
			 com.sun.midp.ssl.MessageDigest md = com.sun.midp.ssl.MessageDigest.getInstance(com.sun.midp.ssl.MessageDigest.ALG_MD5, true);
			
			 md.update(s.getBytes(), 0, s.length()) ;

			 System.out.println("test1");
			 
			 System.out.println("tested ab");
			 
			 short sh = md.doFinal(s.getBytes(), 0, s.length(), ab, 0 );
			 
			 System.out.println("called");
			 
		 } catch (CryptoException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		 }
 
		 return toHexString(ab) ;
	}

I used System.out.prin tln to debug, "tested ab" printed but "called" IS NOT printed, so i guess the null pointer is came from short sh = ..........

Why nullpointer?
I dont see which one is null pointer.

anyone help ?
thanks.

Print out the values of md and s as well before the line with

[CODE=java]short sh = md.doFinal(s.ge tBytes(), 0, s.length(), ab, 0 );[/CODE]

[nickyeng]

What is the string that you are passing to genHash function??

what i pass is

"ME REG 123 123 12"

[r035198x]

what i pass is

"ME REG 123 123 12"

Did you print out the values of md and s?

[nickyeng]

Print out the values of md and s as well before the line with

[CODE=java]short sh = md.doFinal(s.ge tBytes(), 0, s.length(), ab, 0 );[/CODE]

these are the values:

ME REG 123 123 12
com.sun.midp.ss l.MD5@d590dbc

[r035198x]

these are the values:

ME REG 123 123 12
com.sun.midp.ss l.MD5@d590dbc

And what are the first six lines of the doFinal method because that is where the NullPointer is being thrown.

[nickyeng]

And what are the first six lines of the doFinal method because that is where the NullPointer is being thrown.

doFinal method is come from com.sun.midp.ss l.MessageDigest class.

[r035198x]

doFinal method is come from com.sun.midp.ss l.MessageDigest class.

Well, you are passing values that cause the execution of the doFinal method to throw a NullPointer Exception then.

[nickyeng]

Well, you are passing values that cause the execution of the doFinal method to throw a NullPointer Exception then.

then based on my above code, which value possibly cause exception ?

[r035198x]

then based on my above code, which value possibly cause exception ?

Hey! What is "ab"? You are also passing ab to the doFinal method and from what I see there, ab is a nice null reference!

[nickyeng]

Hey! What is "ab"? You are also passing ab to the doFinal method and from what I see there, ab is a nice null reference!

exactly.

now i make it ab = new byte[25];

and it works fine now.

---
but i have another problem...which my midlet on my phone cannot send out the sms.